Diffusion, Osmosis, Active Transport Flashcards
(11 cards)
What is the definition of diffusion?
The net movement of particles from an area of high concentration to low concentration
What does diffusion transport?
Gases + liquids
What is the definition of osmosis?
The net movement of water molecules across a partially permeable membrane from high water concentration to low water concentration.
What is the definition of active transport?
Movement of molecules across a cell membrane from a low concentration to a high concentration. Requiring energy from cellular respiration
How are root hair cells adapted for active transport?
- large surface area
- lots of mitochondria to provide energy
- thin walls
How does active transport gain energy?
From cellular respiration (mitochondria)
What is the main difference between diffusion and osmosis to active transport?
Diffusion and osmosis are passive processes as they go with the concentration gradient, unlike active transport which goes against concentration gradient
How do molecules pass through different cells?
Diffusion through the cell membrane
What is the potato experiment for osmosis?
- cut up potato into identical cylinders
- measure the initial mass of each potato cylinder
- put one piece into a beaker of pure water, one into a beaker of very concentrated sugar solution and another in a more concentrated sugar solution
- leave the potato’s for 24 hours
- take out the potato and dry with a paper towel and measure the masses again
- if potato taken in water by osmosis, mass will have increased
- if potato drawn out water by osmosis, mass will decrease
- calculate a percentage change in mass to compare the effects of sugar concentration
Why is active transport important for human life?
Means nutrients in gut can be transferred to the blood where it can be transported around the body
What does an organisms surface area to volume ratio effect?
How easily / quickly an organism can exchange substances e.g. by osmosis
